Participation is a complex multidirectional construct that is influenced by social, attitudinal, and physical aspects of the environment, in addition to being an indicator of social inclusion, health and well-being. The family of participation-related constructs includes attendance and involvement in relevant activities, to capture the participatory experiences of children and youth. In recent years, instruments to assess participation in different environments have been developed, facilitating the incorporation of this assessment into the physiotherapist's clinical practice, as participation represents an important outcome in rehabilitation. The Participation and Environment Measure - Children and Youth (PEM-CY) was developed from the theoretical framework of the International Classification of Functioning, Disability and Health (ICF). The PEM-CY was translated into Portuguese, but its psychometric properties have not yet been verified in the Brazilian population.

To verify the psychometric properties of the PEM-CY Brazil (internal consistency and construct validity) in Brazilian children and young people.

Participants were 101 Brazilian children and adolescents (mean age 9.36 years, SD 3.47) with and without disabilities. Parents or guardians answered the PEM-CY Brazil questionnaire that assesses Participation (Frequency, Involvement and Desire for Change) and Environment (supports, barriers, environmental helpfulness, environmental resources, and overall environmental support). The internal consistency of all subscales was assessed using Cronbach's Alpha. Construct validity was analyzed by comparing the PEM-CY results between groups of children with and without disabilities using the Mann-Whitney or Chi-square tests, considering p<0.05.

Internal consistency ranged from good to excellent for all subscales of the participation section (α=0.70 to 0.84) and all subscales of the environment section (α=0.53 to 0.95). The comparative analysis between groups identified that children with disabilities participated in a small number of activities (p=0.000) and were less involved in all settings (home p=0.007, school and community p=0.000); showed a lower frequency of participation in the community (p=0.000) and a greater desire to change at school (p=0.007) when compared to their peers without disabilities. The guardians of children with disabilities perceived higher barriers at home (p=0.002), school, and community (p=0.000) and fewer supports at home (p=0.001), school and community (p=0.000). The group with disabilities also reported fewer environmental helpfulness at home (p=0.005), school (p=0.000) and community (p=0.000); less environmental resources at home (p=0.002), school (p=0.000) and community (p=0.010); and fewer overall support in all settings (p=0.000).

The results support the reliability and validity of PEM-CY to measure participation at home, at school and in the community, and to verify the characteristics of the environment of Brazilian children and young people with and without disabilities.

The instrument represents an important resource to be used in research and in the clinical practice of rehabilitation professionals, who will be able to evaluate the participation of children and young people, as well as incorporate it as an outcome of interest in interventions.